The present invention generally concerns shaft bearings. More particularly, the invention relates to a shaft bearing having an improved seal arrangement.
Shaft bearings are typically designed having an inner ring and an outer ring, each defining an annular raceway situated in opposition to one another. Bearing elements are disposed in an area defined between the opposed raceways, thereby permitting the rotational displacement of the inner and outer rings with respect to one another. To facilitate this relative rotation, such bearings are generally configured so that a lubricant may occasionally be conducted into the bearing area.
In a typical configuration, lubricant is conducted under pressure into the bearing area. The bearing area is outwardly bounded by the outer ring and inwardly bounded by the inner ring such that a gap may exist between the outer and inner rings on one or both axial ends of the bearing area. To retain the pressurized lubricant, a seal assembly is often disposed in the open gap(s). Such a seal assembly may include an annular member, for example a metallic stamping, extending radially inward from the outer ring toward the inner ring. Because the inner ring rotates with respect to the outer ring, an appropriate gap is generally provided between the annular ring and the inner ring.
Accordingly, a resilient seal is often disposed on the inner ring to seal the gap between the inner ring and the annular ring. One such seal is disclosed in U.S. Pat. No. 4,575,265, the disclosure of which is incorporated herein by reference. The seal of the '265 patent is held in position against the annular ring by a collar which holds the bearing in position about a shaft. The seal is a V-ring type seal having an annular lip abutting the outer surface of the annular ring. This configuration allows lubricant in the bearing area to be forced out of the area beyond the seal but such that moisture and other foreign matter are inhibited from passing inwardly into the bearing area past the seal. Such an arrangement permits the purging of foreign material from the bearing area while protecting the bearing area from ingress of such foreign material.